Non-rigid surgical retractor

ABSTRACT

The present invention provides a non-rigid retractor for providing access to a surgical site, such as a patient&#39;s spine, during a surgical process. When used in spinal surgery, the non-rigid retractor allows a surgeon to operate on one or more spinal levels. The non-rigid retractor includes at least one flexible strap anchored at a first end to the spine or other internal body part at the surgical site. The body of the at least one flexible strap extends from a skin incision and is anchored at a second location external to the body to retract skin and muscle from the surgical site, allowing adequate visualization of the surgical site and providing access for implants and surgical instruments to pass through the retractor and into the surgical site

RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 11/540,780 (Attorney Docket NumberDUQ-021/DEP5663USNP) entitled “NON-RIGID SURGICAL RETRACTOR,” filed onSep. 29, 2006, the contents of which are hereby incorporated byreference. This application claims the benefit of U.S. PatentApplication Ser. No. 60/756,378, filed Jan. 5, 2006, the contents ofwhich are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a device and method for accessing asurgical site during surgery, such as spinal surgery. More particularly,the present invention relates to a device and method for retractingtissue surrounding a surgical site during a surgery.

BACKGROUND OF THE INVENTION

Spinal retraction systems are used in spinal surgery to provide accessto a patient's spine by retracting and holding back tissue from atargeted surgical site beneath the skin. Current spinal retractionsystems are rigid and therefore have difficulty conforming to patientanatomy. The rigid nature of such spinal retraction systems may alsolead to increased danger to skin, nerves, vessels or muscle tissue, andoften an inability to get good muscle retraction at a desired location.In addition, rigid retractors require a bed-mounted arm to hold theretractor in place relative to the patient's body.

SUMMARY OF THE INVENTION

The present invention provides a non-rigid retractor for providingaccess to a surgical site, such as a patient's spine, during a surgicalprocess. When used in spinal surgery, the non-rigid retractor allows asurgeon to operate on one or more spinal levels. The non-rigid retractorincludes at least one flexible strap anchored at a first end to thespine or other internal body part at the surgical site. The body of theat least one flexible strap extends from a skin incision and is anchoredat a second location external to the body to retract skin and musclefrom the surgical site, allowing adequate visualization of the surgicalsite and providing access for implants and surgical instruments to passthrough the retractor and into the surgical site.

In accordance with a first aspect of the present invention, a non-rigidretractor for retracting tissues in an incision for a surgical site isprovided. The non-rigid retractor comprises a flexible strap formed atleast partially of a biocompatible material and a first anchor foranchoring a first portion of the flexible strap to a body part withinthe incision.

In certain embodiments, the non-rigid surgical retractor may comprise aplurality of flexible straps anchored to and extending about theperiphery of the surgical incision.

In accordance with another aspect of the present invention, a method isprovided for providing access to a surgical site in a patient. Themethod comprises the steps of attaching an anchor on a distal end of aflexible strap formed of a biocompatible material to a bone in thesurgical site through an incision; and pulling a proximal end of theflexible strap out of the incision.

In accordance with another aspect, an anchoring device is provided foranchoring one or more flexible straps external to the incision. Theanchoring device may comprise a ring having a central opening forsurrounding the incision and anchoring means distributed on theperiphery of the ring. Each anchoring means is configured to receive andretain a portion of a flexible strap anchored at one end to an internallocation within an incision accessing a surgical site.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other objects, features and advantages of theinvention will be apparent from the following description and apparentfrom the accompanying drawings, in which like reference characters referto the same parts throughout the different views. The drawingsillustrate principles of the invention and, although not to scale, showrelative dimensions.

FIG. 1 illustrates an embodiment of a non-rigid surgical retractor of anillustrative embodiment of the invention.

FIG. 2 illustrates an embodiment of a non-rigid surgical retractorincluding a plurality of flexible straps according to an illustrativeembodiment of the invention.

FIG. 3 illustrates an embodiment of a non-rigid surgical retractorincluding a plurality of flexible straps anchored using an anchoringring according to an illustrative embodiment of the invention.

FIG. 4 illustrates an embodiment of an anchoring ring.

FIG. 5 illustrates another embodiment of an anchoring ring.

FIG. 6 illustrates an embodiment of a non-rigid surgical retractorincluding a plurality of flexible straps connected distally to a ringaccording to an illustrative embodiment of the invention.

FIG. 7 illustrates a flow diagram for an exemplary embodiment of amethod of using a non-rigid retractor of the invention.

FIG. 8A illustrates an embodiment of a retractor/guide and drill used ininstalling a non-rigid retractor of the invention.

FIG. 8B illustrates an embodiment of an inserter tool used in installinga non-rigid retractor of the invention

FIGS. 9A and 9B illustrate an embodiment of a system for inserting anon-rigid retractor of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an improved surgical device and methodfor retracting tissue from an incision and providing access to asurgical site in a patient. The present invention will be describedbelow relative to certain exemplary embodiments in spinal surgery toprovide an overall understanding of the principles of the structure,function, manufacture, and use of the instruments disclosed herein.Those skilled in the art will appreciate that the present invention maybe implemented in a number of different applications and embodiments andis not specifically limited in its application to the particularembodiments depicted herein. For example, while the illustrativeembodiment of the invention relates to a spinal retractor used in spinalsurgery, the non-rigid surgical retractor may be used in any surgicalprocess where access to a surgical site is required.

FIG. 1 illustrates an embodiment of a non-rigid surgical retractor 10 ofan illustrative embodiment of the invention. The illustrative surgicalretractor 10 comprises at least one flexible strap 12 formed of aflexible, biocompatible material. The flexible strap 12 includes a firstend 120 that is anchored to the spine, for example, a vertebra, or otherbody part in a surgical site via a bone anchor 122. When implanted in anincision in the skin for accessing a surgical site, the body of theflexible strap 124 extends out of the incision, and a second portion ofthe flexible strap, such as the second end 126, anchors to a selectedlocation external to the incision. When implanted, the flexible body 124retracts and retains the tissue surrounding the anchored portion of thesurgical site to provide access for instruments and surgical implants tothe surgical site.

The non-rigid surgical retractor 10 may comprise any suitable number offlexible straps 12. For example, the embodiment of FIG. 2, the non-rigidsurgical retractor 10 comprises a pair of flexible straps 12A and 12Banchored to a surgical site and extending external to an incision 200 ina patient's skin for accessing the surgical site. As shown in FIG. 2,each flexible strap 12A and 12B is pulled against the tissue to retractthe tissue in the incision 200. External anchors 224A and 224B anchorthe straps 12A, 12B external to the incision to hold the tissue in theretracted position.

Alternatively, the non-rigid surgical retractor 10 comprises a singleflexible strap, as shown in FIG. 1, or several flexible straps that aredistributed about the periphery of the incision for accessing thesurgical site. Different sized and shaped straps can be used to limittissue creep during retraction.

The material forming the body 124 of the flexible strap may comprise anysuitable biocompatible material suitable for retracting tissue. Examplesof suitable materials include, but are not limited to: wool, silk,cotton, linen, hemp, ramie, jute, acetate, acrylic, lastex, nylon,polyester, rayon, spandex, carbon fiber, fiberglass, includingPTFE-coated fiberglass and silicon-coated fiberglass, Kevlar, Teflon,ceramic, carbon, graphite, rubber, Polyglycolic Acid (PGA), Poly1-Lactid Acid (PLA), PTFE, stainless steel, aluminum, titanium, andcombinations thereof. In some embodiments the flexible straps may beformed of a radiolucent material or resorbable material.

In some embodiments an illuminant can be coupled to the flexible strapto provide illumination at the incision site. In one example, theilluminant may be a luminescent chemical coupled to the flexible straps.In one such embodiment, the strap itself is treated with a luminescentchemical. In another such embodiment, a luminescent chemical is providedin tubing attached to the straps. In another example, fiber opticsattached to or embedded in the straps may be used to provideillumination at the incision site.

In certain embodiments the flexible straps may be coated withtherapeutic agents allowing the flexible straps to be used for drugdelivery at the surgical site. For example, pain medication,antibiotics, anti-inflammatories, and other medications may be appliedto the flexible straps and delivered at the incision site by theflexible strap. Additionally, the straps may contain adhesives topromote wound closure.

Other possible sizes, shapes, materials, and configurations will beapparent to one skilled in the art given the benefit of this disclosure.

The bone anchor 122 for attaching the flexible strap 12 to a bone orother body part may comprise any suitable device for anchoring theflexible strap to a body part such as a screw, pin, or the like. Forexample, in one embodiment, the bone anchor 122 comprises a resorbableanchor. Alternatively the bone anchor 122 may comprise a biocompatibleanchor formed of a non-resorbable material. The anchor 122 may attachdirectly to the bone or body part. Alternatively, an intermediateanchor, such as pedicle screws fixed to pedicle bone in the spine, maybe used to connect a flexible strap 12 to the body part.

The second portion 126 of the flexible strap 12 may be anchored externalto the incision using any suitable means. Examples of suitable externalanchoring mechanisms include, but are not limited to, Velcro, adhesive,tape, clips, snaps or other suitable anchoring means known in the art.Other possible anchoring mechanisms will be apparent to one skilled inthe art given the benefit of this disclosure.

In one embodiment of the invention, shown in FIG. 3, the externalanchoring mechanism may comprise a ring 30 configured to rest on theskin, surrounding the incision site 200 and having a plurality ofexternal anchoring mechanisms 31 distributed about the periphery of thering for receiving a second portion 126 of the flexible strap(s) 12. Acentral opening 32 in the ring 30 provides access to the incision site200. The anchoring ring 30 may have any suitable shape, size andconfiguration and is not limited to a round shape. Additional shapessuch as triangles, rectangles, or other geometries are possible.

The ring 30 may have any configuration suitable for anchoring one ormore flexible retraction straps while providing access to the surgicalsite. For example, as shown in FIG. 4, an anchoring ring 300 for aretraction strap may comprise a plurality of peripheral slots 310 abouta central opening 320 for receiving and retaining a portion of aretraction strap by friction fit. This configuration allows control overretraction force as the surgeon can pull the retraction strap to retracttissue farther back, or loosen the strap to release the tissue.

According to another embodiment, an anchoring ring 300′, shown in FIG.5, may comprise a plurality of clamps distributed about a peripheralopening. In this example, the clamps 330 can be screwed down, here usingthumb screws 335, to secure the retraction strap to the anchoring ring300′. In other embodiments, the clamps may be spring loaded. In someembodiments, the clamping mechanism may include a ratcheting mechanism.The retracting strap could be placed into the ratcheting mechanism andtightened thereby retracting the tissue. The ratcheting mechanismmaintains tension on the retracting strap while allowing for furthertightening and thus retraction of tissue.

According to another embodiment of the invention, a non-rigid surgicalretractor 10′ can comprise a distal connection member 1240, here a ring,having one or more flexible straps 12 attached thereto, as shown in FIG.6. The flexible straps 12 may be permanently or removably attached tothe distal connection member 1240. The distal connection member 1240 isfixed to a body part at a surgical site, such as the spine, withanchors, such as pins, screws, clips, staples, resorbable fixationdevices, and other anchoring means known in the art. Alternately, thedistal connection member 1240 may be deformed to fit around the spinalanatomy, like a rubber band, using no anchors but the tension of thering. The distal connection member 1240 is preferably deformable tofacilitate insertion of the retractor into the incision. The member 1240may deform from an initial configuration to a collapsed configuration,whereupon release it may return to the initial configuration. The member1240 may be formed of any suitable material, such as, but not limitedto, rubber, plastic and flexible metal. The distal connection member1240 may have any suitable shape and is not limited to a round shape.When the distal connection member 1240 is attached to a body part at asurgical site, the flexible straps extend from an incision for accessingthe surgical site and are used to hold back the soft tissue within theincision. The flexible straps 12 may be anchored external to theincision using any suitable external anchoring means.

FIG. 7 is a flow diagram 700 for one exemplary method of providingaccess to a surgical site in a patient using a non-rigid retractor.First, an incision is made at the surgical site 710. The incision sitemay then be prepared for the insertion of the non-rigid retractor 720.The non-rigid retractor can then be inserted into the incision site 730.Once inserted, the non-rigid retractor can then be used to retracttissue from the surgical site 740.

In one embodiment, the step of preparing the incision (step 720)involves additional steps. For example, blunt finger dissection betweenmuscle planes may be performed. Continuous or serial dilation with orwithout a guide wire may be performed to expand the incision opening forinsertion of a guide or retractor. Then a guide or retractor can beinserted into the incision. The guide or retractor can be used to sweepback muscle and tissue from the surgical site to find a target forattaching a flexible strap formed of a biocompatible material. Anexample of suitable retractor/guide can be seen in FIG. 8A. Here theretractor/guide 800 features a hollow insertion cannula 810 for guidingthe insertion and removal of surgical instruments, including thenon-rigid retractor, and a handle 820 attached to the proximal end ofthe cannula 810 for inserting and positioning the insertion cannula 810in the incision site. Once a target for attaching a flexible strap islocated a drill 840 or awl may be used to create an anchor hole forattaching the flexible strap. Examples of suitable targets includeportions of a vertebra, such as a pedicle, vertebral body, spinousprocess, transverse process, lamina, facet or the like. In certainembodiments intermediate anchors such as pedicle screws can be used forattaching the flexible strap.

Referring again to FIG. 7, the step of inserting the non-rigid retractor(step 730) may also involve multiple steps. In one example, these stepsinclude attaching an anchor on a distal end of flexible strap formed ofa biocompatible material to a bone in the surgical site through theincision and pulling a proximal end of the flexible strap out of theincision. In some embodiments this involves using the retractor/guideshown in FIG. 8A. In such an example, the hollow insertion cannula 820of the retractor/guide 800 is inserted in the incision. An anchor of theflexible strap is passed through the hollow insertion cannula 820 suchthat the body of the flexible strap extends through a hollow opening inthe hollow insertion cannula 820. The anchor of the flexible strap isthen attached to the target. The hollow insertion cannula 820 of theretractor/guide 800 may then be withdrawn from the insertion so that theflexible strap extends from the incision. In some embodiments aninsertion tool 850 as shown in FIG. 8B is used. The inserter tool 850 isused to pass the anchor of the flexible strap though the insertioncannula and attach the anchor to the target.

In another embodiment shown in FIGS. 9A and 9B, a system 900 is providedin which the guide, such as a cannula 910, is pre-loaded with anon-rigid retractor. In the example of FIGS. 9A and 9B the non-rigidretractor comprises four flexible straps 920 each with an anchor 930 foranchoring the respective flexible strap 920. It should be noted howeverthat the non-rigid retractor may have any number of flexible straps asdiscussed with regard to embodiments above. With the non-rigid retractorpreloaded in the cannula 910, the process of inserting the cannula 910into the incision also serves to insert the non-rigid retractor. Oncethe system 900 is in position, the anchors 930 of the flexible straps920 can be attached to the target. The cannula 910 of the system 900 maythen be withdrawn from the insertion so that the flexible straps 920extend from the incision.

In some embodiments an insertion tool is used to attach an anchor 930 toa target. In certain embodiments, the insertion tool may be part of thesystem 900. In the example of FIGS. 9A and 9B, the insertion tool 950 isa plunger-type mechanism mounted on a center spindle 952 allowing theinsertion tool 950 to rotate so that the distal end 954 of the insertertool 950 can engage the anchors 930 of the flexible straps 920 attachingthe anchors 930 to the target using the plunger action of the insertiontool 950.

It should be understood that the examples of FIGS. 9A and 9B are but oneof many possible examples of a system. Other possible guides,configurations, and insertion tools will be apparent to skilled in theart given the benefit of this disclosure.

Once the non-rigid retractor has been inserted, it can then be used toretract tissue at the surgical site (step 740). In some embodiments,this involves retracting tissue surrounding the incision using theflexible strap and anchoring the proximal end of the flexible strapexternal to the incision. In certain embodiments this can be performedusing an anchoring ring. In one such example this involves placing ananchoring ring having a central opening for surrounding the incisionsite and anchoring portions distributed on the periphery of the ring forreceiving the proximal end of the flexible strap externally over theincision. The proximal end of the flexible strap can then be secured inan anchoring portion distributed on the periphery of the ring. In otherembodiments, the proximal end of the flexible strap may be securedwithout the use of an anchoring ring. For example, the proximal end maybe self-adhesive allowing the proximal end to be secured to the patient,or the proximal end may be secured to the patient or drape using clips.

The process set forth in FIG. 7 and discussed above can then be repeatedto place a number of flexible straps to retract tissue at a surgicalsite. Once sufficient retraction of the tissue is obtained, necessarysurgical procedures may then be performed at the surgical site. Afterthe procedure has been performed at the surgical site, one or moreflexible straps may be disconnected and removed allowing the incision tobe closed. As discussed above, many of the components of the non-rigidretractor, such as the anchor or strap, may be made of a bio-absorbableor biocompatible material such that components, like the anchors orstraps, may be left in the body of the patient.

The apparatus and techniques of the present invention provide numerousadvantages. The non-rigid retractor of the present invention can be usedin any approach, including lateral, posterior, and anterior. Thenon-rigid retractor is highly adaptive, in that additional straps can beused for additional retraction. The flexible nature of the strapsprevents damage to tissue, vessels, and muscle and alleviates the needfor a bed-mounted arm to secure the retractor. The retractor may also besecured to an anchor ring or to the patient's skin which may eliminatethe necessity of a bed mounted arm. The flexible nature of the strapsallows the retractor to be easily adjusted to provide varying amounts oftension on the retracted tissue.

Although the present invention has been described relative to anillustrative embodiment and application in spinal correction surgery, itshould be apparent that the present invention may be used in any numberof surgical procedures. Since certain changes may be made in the aboveconstructions without departing from the scope of the invention, it isintended that all matter contained in the above description or shown inthe accompanying drawings be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are to cover allgeneric and specific features of the invention described herein, and allstatements of the scope of the invention which, as a matter of language,might be said to fall therebetween.

1. A non-rigid retractor for retracting tissues in an incision for asurgical site, comprising: a flexible strap formed at least partially ofa biocompatible material; and a first anchor for anchoring a firstportion of the flexible strap to a body part within the incision.